Retaining rings are utilized in annular grooves on shafts and ends of shafts to retain bearings, collars and the like on the shaft. A retaining ring extends circumferentially between a pair of ends which have hubs. The hubs have apertures which receive tips of a plier tool. The force applied by the pliers either spread the hubs to expand the ring or squeezes the hubs to contract the ring. The plier tool is necessary for installing the retaining ring in and removing the retaining ring from either external or internal grooves.
Accordingly, it is sometimes desirable to squeeze the handles to effect movement of the jaws outwardly to expand the ring. It is at other times desirable to squeeze the handles to effect movement of the jaws inwardly to contract the ring. Thus, it is desirable to provide a pliers that is convertible between an external and an internal tool. U.S. Pat. Nos. 4,280,265 and 4,476,750 disclose a pair of retaining ring pliers that utilize a pair of separate co-planar jaws and a pair of separate handles that range about a common fixed pivot point and that are adapted to be changed to alternately engage one handle to one jaw and the other handle to the other jaw and vice versa to permit the changing of the tool from external to internal and vice versa. Two fulcrum or transfer pins of a latching arrangement are disposed in the jaws and are adapted to alternately engage each set of the handles to shift from a position adapted to move the jaws inwardly as the handles are moved inwardly, and to a position where the jaws are moved outwardly as the handles are moved inwardly.
The prior art retaining ring pliers in the '265 and the '750 patents require that a user have a dull pointed instrument, such as a pen, nail or screwdriver, handy to forcefully push the pins between their alternate positions. Specifically, the user would have to squeeze the handles of the pliers inwardly to align the transfer pins of the latching arrangement with the holes formed in the handles, and then use the pointed instrument to push the pins from each respective side of the pliers. Thus, each of the transfer pins disclosed in the above-noted patents has to be independently placed in the correct position using an additional tool.
A convertible retaining ring pliers that does not require another instrument or tool to convert the pliers between internal and external modes is disclosed in U.S. patent application Ser. No. 10/818,251 filed Apr. 5, 2004 by the assignee of this application. In this design, a switching mechanism is mounted to the plier's handles and pivot for providing simultaneous shifting of the transfer pins in the jaws and handles between first and second operating positions. The switching mechanism includes a first flexing spring plate disposed on an external surface of the first handle, and a second flexing spring plate disposed on an external surface of a second handle. Each of the spring plates have a pair of boss pins engageable with opposite ends of the transfer pins. Finger pressure is simultaneously applied to the ends of the spring plates while the handles are moved inwardly to simultaneously shift the transfer pins between the first and second operating positions.
Accordingly, it is desirable to provide a convertible retaining ring pliers that does not require another instrument or tool to convert the pliers from internal to external mode and vice versa. It is further desirable to provide a relatively simple switching mechanism which does not require finger pressure to be simultaneously applied to the transfer pins from each side of the pliers, while the handles are moved inwardly to align the transfer pins with the proper holes in the handles. It is preferable that the simultaneous movement of the transfer pins will make the conversion faster and more efficient than previous models with far less complexity required in the pliers structure.